当SQL中存在空值时，在VBA标签中显示标题"No results“

Sub DisplayResults()
    Dim conn As Object
    Dim rs As Object
    Dim strSQL As String
    Dim resultLabel As Object
    
    ' 连接到数据库
    Set conn = CreateObject("ADODB.Connection")
    conn.Open "Provider=SQLOLEDB;Data Source=数据库服务器;Initial Catalog=数据库名称;User ID=用户名;Password=密码;"
    
    ' 执行SQL查询语句
    strSQL = "SELECT * FROM 表名 WHERE 列名 IS NULL"
    Set rs = conn.Execute(strSQL)
    
    ' 检查结果集中是否存在空值
    If rs.EOF Then
        ' 结果集为空，显示"No results"
        Set resultLabel = ThisWorkbook.Sheets("Sheet1").Shapes("Label1")
        resultLabel.TextFrame2.TextRange.Text = "No results"
    Else
        ' 结果集不为空，处理结果集
        ' ...
    End If
    
    ' 关闭连接
    rs.Close
    conn.Close
    Set rs = Nothing
    Set conn = Nothing
End Sub